HG-02A PHASE 1/2 TRIAL OF THE ANTIBODY PIDILIZUMAB (MDV9300) IN PEDIATRIC DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract

Background: Diffuse intrinsic pontine glioma (DIPG) is an incurable disease with a median overall survival of 10 months. Multiple past trials failed to show benefit of all chemo/radiotherapy regimens which were tested. Lately, anti PD1 antibodies emerged as a highly promising treatment modality in multiple cancer types. We present Results from the first study evaluating anti pd1 antibodies in pediatric patients with DIPG. Methods: Patients diagnosed with DIPG based on clinical and imaging criteria, were started on the anti PD1 antibody MDV9300 biweekly at a dose of 6 mg/kg. Treatment was initiated at least 2 weeks after radiation completion. Treatment was continued until disease progression on imaging. The study was opened on February 2014. Results: Eight patients were enrolled. A total of 73 cycles of MDV9300 (range 2‐16) were applied. Treatment was well tolerated. Main side effects were neutropenia (CTCEA grade 1‐3), mild to moderate fatigue and acute elevation of blood pressure following 15%, 10% and 1.3% of the cycles respectively. Two of our 8 patients are alive and well more than 18 months from diagnosis. One patient had tumor shrinkage of > 50% 10 months after treatment initiation and is well after protocol completion (19mo from diagnosis). A second patient is stable on treatment 18.3 months after diagnosis. Survival at 6 and 12 months was 100 and 50% respectively. Conclusion: Anti PD1 treatment is a well‐tolerated therapy with possible activity in DIPG.